The authors regret that Figure 6(a) and Figure 6(b) were incorrectly ordered in their original paper and apologise for any inconvenience caused. The correct version of Figure 6 is shown below:

Figure 6

FTIR spectra of rice straw (a) pre- versus post-biosorption of Pb2+ (particle size: 75–150 μm, Co: 60 mg/l), (b) pre-biosorption of Pb2+ (particle size <75 μm).

Figure 6

FTIR spectra of rice straw (a) pre- versus post-biosorption of Pb2+ (particle size: 75–150 μm, Co: 60 mg/l), (b) pre-biosorption of Pb2+ (particle size <75 μm).